More than half the world's population of seven billion now live in cities, and cities are responsible for 70% of greenhouse gas emissions globally. Roughly 75% of that pollution is under the direct control of city governments, including the ability to enact green building codes.
With countries not tackling climate change aggressively, cities are in the best position to drive increased sustainability. “We will spend more and build more in the next century than we have in all of human history before this” says urban theorist Richard Florida. “Our cities have to be more environmentally sustainable.”